SpaceX may still be private, but an increasingly crowded ecosystem is emerging around one simple investor obsession: getting a piece of Elon Musk's rocket giant before any IPO arrives.

A series of recent SEC Form D filings shows that private investment vehicles tied to SpaceX exposure have quietly raised millions of dollars from dozens, and sometimes hundreds, of investors.

The catch? Entry into this unofficial SpaceX marketplace often starts around $25,000.

The filings paint a picture of what increasingly looks like a parallel stock market forming around one of the world's most sought-after private companies.

The $25K Backdoor Into SpaceX

One filing for "HII SpaceX Series II" disclosed nearly $15.9 million raised from 150 investors, with a minimum investment amount of $25,000. Another filing tied to Hiive, a secondary marketplace for private-company shares, showed a separate SpaceX-focused opportunity fund raising $6 million with the same $25,000 minimum buy-in.

The structures vary. Some are SPVs, or special purpose vehicles, designed solely to hold SpaceX shares. Others resemble feeder funds or syndicates pooling investor ...